This document provides an index and overview of the layout of a substation.
1. The index lists 14 topics that will be covered, ranging from bus bars and isolators to transformers and circuit breakers.
2. The introduction explains that electric power is transmitted through a network of substations, which change characteristics of the electric supply like voltage.
3. Outdoor substations like the 220KV GSS Sanganer are described, which have one and half breaker schemes and feed power to locations like KTPS and Sakatpura.
Introduction, Operation of 12-pulse converter as receiving and sending terminals of HVDC system, Equipment required for HVDC System and their significance, Comparison of AC and DC transmission, Control of HVDC transmission
Since the loads having the trends towards growing density. This requires the better appearance, rugged construction, greater service reliability and increased safety. An underground cable essentially consists of one or more conductors covered with suitable insulation and surrounded by a protecting cover. The interference from external disturbances like storms, lightening, ice, trees etc. should be reduced to achieve trouble free service. The cables may be buried directly in the ground, or may be installed in ducts buried in the ground.
A switchgear or electrical switchgear is a generic term which includes all the switching devices associated with mainly power system protection. It also includes all devices associated with control, metering and regulating of electrical power system. Assembly of such devices in a logical manner forms a switchgear. This is the very basic definition of switchgear.
⋗To get more with details
https://www.youtube.com/channel/UC2SvKI7eepP241VLoui1D5A
PPT ON 220KV Grid sub-station at Gandhi nagar, Jagatpura, Jaipur
It's very easy ppt for electrical engineering & EC engineering student for training of gss.
you can see my ppt on Slidshare...
Introduction, Operation of 12-pulse converter as receiving and sending terminals of HVDC system, Equipment required for HVDC System and their significance, Comparison of AC and DC transmission, Control of HVDC transmission
Since the loads having the trends towards growing density. This requires the better appearance, rugged construction, greater service reliability and increased safety. An underground cable essentially consists of one or more conductors covered with suitable insulation and surrounded by a protecting cover. The interference from external disturbances like storms, lightening, ice, trees etc. should be reduced to achieve trouble free service. The cables may be buried directly in the ground, or may be installed in ducts buried in the ground.
A switchgear or electrical switchgear is a generic term which includes all the switching devices associated with mainly power system protection. It also includes all devices associated with control, metering and regulating of electrical power system. Assembly of such devices in a logical manner forms a switchgear. This is the very basic definition of switchgear.
⋗To get more with details
https://www.youtube.com/channel/UC2SvKI7eepP241VLoui1D5A
PPT ON 220KV Grid sub-station at Gandhi nagar, Jagatpura, Jaipur
It's very easy ppt for electrical engineering & EC engineering student for training of gss.
you can see my ppt on Slidshare...
It's a full fledged presentation about visit to a substation. It's about when we visited the 400 kV substation situated at Hadala, Rajkot, Gujarat, India. It includes almost aa details about it. Juz go for it!!!
Training from 220kv GSS Sanganer, which is located on Muhana Road, JaipurR-One Power
The technology all about GSS System and their operating system.
In the presentation all about the GSS and their instrument which has used in GSS for operation and controlling the whole system.
I hope this presentation helpfull to all those students, who had their training from Sanganer 220kv GSS.
Operational description of 400kv switchyard NTPC Ramagundam RSTPSPradeep Avanigadda
400 KV Switchyard of Ramagundam Super Thermal Power Station is the most vital switching station in the southern Grid. 2600 MW of Bulk Power generated by three 200 MW Units and four 500 MW Units of NTPC Ramagundam is evacuated for supplying to the southern states.
Switchyard consists of four 400 KV busbars fed by 7 Nos. of generators, 10 Nos. of 400 KV feeders, 3 Nos of 220 KV feeders and two nos. of 132 Kv feeders as shown in the single line diagram of 400 Kv switch yard.
In addition to the above, four nos. of Tie Transformers, five nos. of Auto transformers, two nos. of Shunt Reactors and one Bus reactor are provided.
The presentation is about the Shanghai Long-distance Bus Station. The station is being managed by Shanghai Nanzhan Long Distance Passenger Transportation Co. Ltd.
Design of a generating substation with the description of designing a transformer. Here we show some basic components of a substation. and we also show the parameters and calculation to design a transformer of a specific ratings.
insulators, conductors, transformer and ac motorsChippa Srikanth
it is basic to know of insulator conductor, transformer and ac motors. it is very useful to all electrical engineers. it is not only for engineers it is easily under standed by every one.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
1. INDEX
LAYOUT pg. no
1. INTRODUCTION [SUB STATION] -1
2. BUS BARS -4
3. ISOLATORS -7
4. PROTECTIVE RELAYS -11
5. CIRCUIT BREAKERS -16
6. POWER TRANSFORMER -25
7. CURRENT TRANSFORMER -31
8. CAPACITIVE VOLTAGE TRANSFORMERS -33
9. TRASNFORMER OIL AND ITS TESTING -36
10. LIGHTENING ARRESTORS -38
11. CONTROL ROOM -41
12. EARTHING OF THE SYSTEM -44
13. POWER LINE CARRIER COMMUNICATION -46
14. CORONA -47
CONCLUSION
REFERENCES
2. INTRODUCTION
Electric power is generated, transmitted and distributed in the form of alternating
current. The electric power produced at the power stations is delivered to the
consumers through a large network of transmission & distribution.
The transmission network is inevitable long and high power lines are necessary to
maintain a huge block of power from source of generation to the load centers to
inter connected. Power house for increased reliability of supply greater.
The assembly of apparatus used to change some characteristics (e.g. voltage, ac to
dc, frequency, power factor etc.) of electric supply keeping the power constant is
called a sub-station.
Depending on the constructional feature, the high voltage sub-stations may be
further subdivided:
a) Out door substation.
b) Indoor substation.
c) Basement or Underground substation.
2 Dept. of Electrical Engg.
3. fig 1
220 KV G.S.S. SANGANER
1) It is an outdoor type substation.
2) It is primary as well as distribution substation.
3) One and half breaker scheme is applied.
3 Dept. of Electrical Engg.
4. The power mainly comes from HIRAPURA-1 and HIRAPURA-2 & KOTA
THERMAL .
Out going feeders
1) One feeder of 220kv to KTPS
2) One feeder of 220kv to Sakatpura.
3) One feeder of 220kv to KTPS2
4) One feeder of 220kv to Phulera
5) One feeder of 400kv to Merta
6) One feeder of 220kv to Sanganer
At this substation following feeders are established.
1. TIE FEEDERS.
2. RADIAL FEEDERS.
TIE FEEDERS:
There are 220KV tie feeders as follows.
1.220 KV KOTA-JAIPUR 1st & 2nd
2. Inter state 220KV KOTA –DELHI
3. Tie from 220 KV Heerapura.
4. 220KV KTPS first & second.
RADIAL FEEDERS
4 Dept. of Electrical Engg.
5. 1. 220 KV JAIPUR –KOTA 1st & 2nd feeders
2. 132KV KOTA –BUNDI 1st
3. 132KV KOTA –SAWAI MADHOPUR 1st & 2nd
4.132 KV KOTA –SANGOD
5. 132 KV KOTA –MORAR
BUS BARS
Bus Bars are the common electrical component through which a
large no. of feeders operating at same voltage have to be connected.
If the bus bars are of rigid type (Aluminum types) the structure heights are low
and minimum clearance is required. While in case of strain type of bus bars
suitable ACSR conductors are strung / tensioned by tension insulator discs
according to system voltages. In the widely used strain type bus bars stringing
tension is about 500 - 900 kg depending upon the size of conductor used.
Here proper clearance would be achieved only if require tension is achieved. Loose
bus bars would effect the clearances when it swings while over tensioning may
damage insulators. Clamps or even effect the supporting structures in low
temperature conditions.
The clamping should be proper, as loose clamp would spark under in full load
condition damaging the bus bars itself.
5 Dept. of Electrical Engg.
6. BUS BAR ARRANGEMENT MAY BE OF FOLLOWING TYPES WHICH
ARE BEING ADOPTED BY R.R.V.P.N.L
1.) Single bus arrangement.
2.) Double bus bar arrangement.
a) Main bus with transformer bus.
b.) Main bus-I with Main bus-II.
3.) Double bus bar arrangement with auxiliary bus.
DOUBLE BUS BAR CONTAINING MAIN BUS I WITH MAIN BUS II:
1. Each load may be fed from either bus.
2. The load circuits may be divided in two separate groups if needed from
operational consideration. Two supplies from different sources can be put on each
bus separately.
3. Either bus bar may be taken out from maintenance and cleaning of insulators.
This arrangement has been quite frequently adopted where the loads and continuity
of supply is necessary. In such a scheme a bus coupler breaker is mostly provided
as it enables on load change over from one bus bar to other.
The normal bus selection isolators cannot be used for breaking load currents. The
arrangement does not permit breaker maintenance without causing stoppage of
supply.
DOUBLE BUS BAR ARRANGEMENTS CONTAINS MAIN BUS WITH
AUXILIARY BUS:
6 Dept. of Electrical Engg.
7. The double bus bar arrangement provides facility to change over to either bus to
carry out maintenance on the other but provide no facility to carry over breaker
maintenance. The main and transfer bus works the other way round .It provides
facility for carrying out breaker maintenance but does not permit bus
maintenance. Wherever maintenance is required on any breaker the circuit is
changed over to the transfer bus and is controlled through bus coupler breaker.
fig 2
7 Dept. of Electrical Engg.
8. ISOLATORS
Isolators which are also called disconnect switches or air break
switches after the assembly as per drawings on the leveled structures the
adjustment of connecting pipes, moving and fixed contacts is done so that all the
three phase of the isolator close and open simultaneously and there is a full surface
contact between moving and fixed contacts. Such switches are generally used on
both sides of equipment in order that repairs and replacement of the equipment can
be made without any danger. They should never be opened until the equipment in
the same circuit has been turned off and should always be closed before the
equipment is turned on.
The adjustment of the tendon pipes leveling of post insulator, stop holts in the
fixed contacts etc. is done for smooth operation of insulator. Following type of
insulator are being used in R.S.E.B-
a) Isolator without earth blades.
b) Isolator with earth blade.
8 Dept. of Electrical Engg.
9. c) Tendon isolator.
INSULATORS
The insulators for the overhead lines provide insulation to the power conductors
from the ground so that currents from conductors do not flow to earth through
supports. The insulators are connected to the cross arm of supporting structure and
the power conductors passes through the clamp of the insulator. The insulators
provide necessary insulation between line conductors and supports and thus
prevent any leakage current from conductors to earth. In general, the insulators
should have the following desirable properties:
1. High mechanical strength in order to withstand conductor load, wind load
etc.
2. High electrical resistance of insulator material in order to avoid leakage
currents to earth.
3. High relative permittivity of insulator material in order that dielectric
strength is high.
4. The insulator material should be non porous, free from impurities and cracks
otherwise the permitivity will be lowered.
5. High ratio of puncture strength to flash over.
These insulators are generally made of glazed porcelain or toughened glass. Poly
come type insulators [solid core] are also being supplied in place of hast insulators
if available indigenously. The design of the insulator is such that the stress due to
contraction and expansion in any part of the insulator does not lead to any defect. It
9 Dept. of Electrical Engg.
10. is desirable not to allow porcelain to come in direct contact with a hard metal
screw thread.
TYPES OF INSULATORS:
There are three types of insulators used for overhead lines:
1. Pin type- pin type insulator consists of a single or multiple shells adapted
to be mounted on a spindle to be fixed to the cross arm of the supporting
structure.
When the upper most shell is wet due to rain the lower shells are dry and
provide sufficient leakage resistance. These are used for transmission and
distribution of electric power at voltage up to voltage 33KV. Beyond
operating voltage of 33KV the pin type insulators thus become too bulky
and hence uneconomical.
Fig 3.1
2. Suspension type- suspension type insulators consist of a number of
porcelain disc connected in series by metal links in the form of a string.
10 Dept. of Electrical Engg.
11. Its working voltage is 66KV. Each disc is designed for low voltage for
11KV.
Fig 3.2
3. Strain insulator- the strain insulators are exactly identical in shape with
the suspension insulators. These strings are placed in the horizontal plane
rather than the vertical plane. These insulators are used where line is
subjected to greater tension. For low voltage lines (<11kV) shackle
insulators are used as strain insulator.
11 Dept. of Electrical Engg.
12. Fig 3.3
PROTECTIVE RELAYS
A Protective relay is a device that detects the fault and initiates the operation of the
circuit breaker to isolate the defective element from the rest of the system.
The relays detect the abnormal condition in the electrical circuits by constantly
measuring the electrical quantities i.e. voltage, current, frequency, phase angle
which are different under normal and fault conditions. Having detected the fault,
the relay operates to close the trip circuit of the breaker, which results in opening
of the breaker and disconnection of the faulty circuit.
Relay circuit connections can be divided in three parts:
1.) Primary winding of a C.T. that is connected in series with the line to be
12 Dept. of Electrical Engg.
13. protected.
2.) Secondary winding of C.T. and the relay operating coil.
3.)Third part is the tripping circuit, which may be either a.c. or d.c. . It consists of a
source of a supply, the trip coil of a circuit breaker and the relays stationary
contacts.
When a short circuit occurs at point F on the transmission line the current
increases to enormous value. This results in a heavy current flow through the relay
coil, causing the relay to operate by closing its contacts. This in turn closes the trip
circuit of the breaker, making the C.B. open and isolating the family section from
the rest of the system. In this way, the relay ensures the safety of the circuit
equipment
from damage and normal working of the healthy portion of the system.
13 Dept. of Electrical Engg.
14. Fig 4
Basic qualities that a protective relay must possess are:
1.) Selectivity
2.) Speed
3.) Sensitivity
4.) Reliability
5.) Simplicity
6.) Economy
DIFFERENTIAL RELAYS
14 Dept. of Electrical Engg.
15. A differential relay is one that operates when the phasor difference of two or more
similar electrical quantities exceeds a predetermined value.
Thus the current differential relay is one that compares the current entering and
current leaving the section. Under normal operating conditions, the two currents
are equal but as soon as fault occurs, this condition is no longer applied.
The difference between the incoming and outgoing currents is arranged to flow
through the operating coil of the relay. If this differential current is equal to or
greater than the pick up value, the relay will operate and open the C.B. to isolate
the faulty section.
BUCHHOLZ RELAY
It is a gas-actuated relay installed in oil immersed transformers for protection
against all kinds of faults. it is used to give an alarm in case of incipient (i.e. slow
developing)faults in the transformer and to disconnect the transformer from the
supply in the event of severe internal faults. it is usually installed in the pipe
connecting the conservator to the main tank. It is a universal practice to use
BUCHHOLZ relay on all such oil immersed transformers having ratings in excess
of 750kVA.
CONSTRUCTION
It takes the form of a domed vessel pipe between the main tank and the
15 Dept. of Electrical Engg.
16. conservator. The device has two elements. the upper element consists
of a mercury type switch attached to a float. The lower element contains
a mercury switch mounted on a hinged type flap located in the direct path
of the flow of oil from the transformer to the conservator. the upper element
closes an alarm circuit during incipient faults whereas the lower element is
arranged to trip the circuit breaker in case of server internal faults.
OPERATION
The operation of Buchholz relay is as follows:
(i)In case of incipient faults within the transformer, the heat due to fault
causes the decomposition of some transformer oil in the main tank the
products of decomposition contain more than 70% of hydrogen gas. the
hydrogen gas being light tries to go into the conservator and in the process
gets entrapped in the upper part of the relay chamber. when a pre determined
amount of gas gets accumulated, it exerts sufficient pressure on the float to
cause it tilt and close the contacts of the mercury switch attached tom it.
This completes the alarm circuits to to sound an alarm.
(ii)If a serious fault occurs in the transformer, enormous amount of gas
is generated in the main tank. The oil in the main tank rushes to the
conservator via the Buchholz relay and in doing so tilts the flap to close
the contacts of the mercury switch. This completes the trip circuit to open
the circuit breaker controlling the transformer.
ADVANTAGES
16 Dept. of Electrical Engg.
17. (i) It is the simplest form of transformer protection.
(ii) It detects the incipient faults at a stage much earlier than possible with
other forms of protection.
DISADVANTAGES
(i) It can only be used with oil immersed transformers equipped with conservator
tanks.
(ii) The device can detect only faults below oil level in the transformer. therefore
separate protection is needed for connecting cables.
CIRCUIT BREAKERS
17 Dept. of Electrical Engg.
18. Thus circuit breakers are used for switching & protection of various parts of power
system. Circuit breaker is a piece of equipment, which can
1) Make or break a circuit either manually or automatically under normal
condition.
2) Break a circuit automatically under fault condition
3) Make a circuit either manually or by remote control under fault conditions.
OPERATING PRINCIPLES
A C.B. consists of fixed and moving contacts called electrodes. Under
normal operating conditions, these contacts remain closed and will not open
automatically until and unless the system becomes faulty. When a fault occurs on
any part of the system, the trip coils of the circuit breaker get energised and the
moving contacts are pulled apart, thereby opening the circuit.
When the contacts of the C.B. are seperated under fault conditions, an arc is
struck between them. The current is thus able to continue until the discharge
ceaeses. The production of arc not only delays the current interruption process but
it also generates enormous heat which may cause damage to the system or to the
C.B.
It is thus necessary to extinguish the arc within the shortest possible time so that
the heat generated by it may not reach a dangerous value.
18 Dept. of Electrical Engg.
19. ARC PHENOMENON
When a short circuit occurs, a heavy current flows through the contacts of the C.B.
before they are opened by the protective system. At the instant when the contacts
begin to separate, the contact area decreases rapidly and large fault current causes
increased current density and hence rise in temperature. The heat produced in the
medium
between contacts is sufficient to ionize the arc or vaporize and ionize the oil. The
ionized air or vapour acts as conductor and an arc is set between the contacts. The
potential difference between the contacts is quite small and is sufficient to maintain
the arc. the arc provides a low resistance path and as a result the current in the
circuit remains uninterrupted so long as the arc persists.
During the arcing period the current flowing between the contacts depends
on the arc resistance. The greater the arc resistance, the smaller the current that
flows between the contacts. The arc resistance depends upon:
(i) Degree of ionization.
(ii) Length of arc.
(iii) Cross section of arc.
CLASSIFICATION OF THE CIRCUIT BREAKERS:
19 Dept. of Electrical Engg.
20. There are several ways of classifying the circuit breakers. However, the most
general way of classification is on the basis of medium used for arc extinction.
The medium used for arc extinction is usually oil, air, sulphur hexafluoride (SF6)
or vacuum. Accordingly, circuit breakers may be classified into:
They are generally classified on the basis of the medium used for arc elimination
(i) Oil circuit breakers, which employ some insulating oil for arc extinction.
(ii) Air-blast circuit breakers in which high pressure air blast is used for
extinguishing the arc.
(iii) Sulphur hexa fluroide C.B. in which SF6 gas is used for arc extinction.
(iv) Vacuum C.B. in which vacuum is used for arc extinction.
SULPHUR HEXAFLOURIDE (SF6) CIRCUIT BREAKER
In such breakers, sulphur hexaflouride (SF6) gas is used as the arc quenching
medium. The sf6 is an electro-negative gas and has a strong tendency to absorb
free electrons. The SF6 circuit breakers have been found to be very effective for
high power and high voltage service.
CONSTRUCTION
20 Dept. of Electrical Engg.
21. The cylindrical large size steel tanks are mounted horizontally parallel to
each other. Each tank consists of SF6 under pressure. The interruption is of multi
break type & is placed along the axis of each tank. The interruption assembly is
supported inside the tank by the vertical bushing, which are mounted near the end
of each tank. Gas at high pressure is supplied to the interrupter from a gas
reservoir.
The bushing are also insulated with SF6 the conductor is in the from of
copper tube supported at both end by porcelain shields. SF6 gas is supplied from
the high pressure tanks. Shields are provided with gasket seals to eliminate leakage
of gas from beginnings.
21 Dept. of Electrical Engg.
23. Fig 5
WORKING
In the closed position of the breaker the contacts remain surrounded by SF6 gas at
a pressure of about 2.8 kg/sq cm. When the breaker operates, the moving contact is
pulled apart and an arc is struck between the contacts. The
movement of the moving contact is synchronised with the opening of a valve
which permits SF6 gas at 14kg/sq cm pressure from the reservoir to the arc
interruption chamber. the high pressure flow of SF6 rapidly absorbs the free
electrons in the arc path to form immobile negative ions which are ineffective as
charge carriers. The result is that the medium between the contacts quickly builds
up high dielectric strength and causes the extinction of the arc. After
the breaker operation the valve is closed by the action of a set of springs.
400 KV SF6 C.B. [RATINGS]: -
Manufacture: BHEL Hyderabad.
Type: HLR245/2503 B.S.
Rated voltage: Normally 420 KV, maximum 440 KV.
Rated frequency: 50 HZ.
Rated power frequency: voltage: 520 KV
Rated Impulse withstand voltage:
Lightning: 1425KV
Switching: 1050KV
23 Dept. of Electrical Engg.
24. Normal current rating
At 50 c ambient: 2240Amps
At 40 c ambient: 2500Amps
Short time current rating: 40 KA for 3 sec.
Rated operating duty: 0 to 0.3 sec. c-0-3min-mb.
Rated short circuit duration: 1 sec.
BREAKING CAPACITY [BASED ON SPECIFIED DUTY CYCLE]:
(a) Capacity at rated voltage: 29000MVA [440KV].
(b) Symmetry current: 40 KA.
(c) Asymmetry current: 49 KA.
Making capacity: 100KA [peak]
Rated pressure of hydraulic operating (gauge): 250-350bar.
Rated pressure of SF6 gas at degree: 7.5bars.
Weight of complete breaker: 11700 Kg.
Weight of SF6 gas: 76.5Kg.
Rated trip coil voltage: 220 V. AC.
Rated closing voltage: 220 V. DC.
24 Dept. of Electrical Engg.
25. First poll to clear factor: 1.3
ADVANTAGES OF SF6 CIRCUIT BREAKER:
1. Due to the superior arc quenching property of SF6, such circuit breakers
have very short arching time.
2. Since the dielectric strength of SF6 gas is 2 to 3 times that of air, such
breakers can interrupt much larger currents.
3. The SF6 circuit breakers gives noiseless operation due to its closed gas
circuit and no exhaust to the atmosphere unlike the air blast circuit breaker.
4. The closest gas enclosure keeps the interior dry so that there is no moisture
problem.
5. There is on risk of fire in such breakers because SF6 gas is not inflammable.
There are no carbon deposits so that tracking and insulation problems are
eliminated.
6. The SF6 breakers have low maintenance cost, light foundation requirement
and minimum auxiliary equipment.
7. Since SF6 breakers are totally enclosed and sealed from atmosphere they are
particularly suitable where explosion hazard exists e.g., coal mines.
25 Dept. of Electrical Engg.
26. DEMERITS OF SF6 CIRCUIT BREKER:
1. Sealing problems arise due to the type of the construction used.
2. The presence of moisture in the system is very dangerous to SF6
circuit breaker.
3. Arced Sf6 gas is poisonous & should not be let out.
4. The double pressure SF6 CB is cost liner due to complex gas system.
5. The internal parts should be cleaned thoroughly during periodic maintenance
under clean dry environment.
6. Dust of Teflon & sulfide should be removed.
7. Special facilities are needed for transporting the gas.
APPLICATIONS
SF6 C.B. have been developed for voltages 115 KV to 230 KV, power ratings 10
MVA to 20 MVA and interrupting time less than 3 cycles.
S.N I.E. MAK TYPE VOLTAGE CURREN STC SF6/HY
O E T D
1 552A 3AT3 3AT3 420/520 2000A 40KA/S 7.5/350
2 552T DO DO DO DO DO DO
3 552B MG FAR2 DO 3150A DO 7/300
4 452T NGEF S2M420 420/610/1425 2000A DO 8/35
5 252A BHEL 3AT3 420/520/1050 DO DO 7.5/350
6 252B ABB EL(V) 420/1050 3150 40KA/3S 7/31.5
26 Dept. of Electrical Engg.
27. POWER TRANSFORMER
The transformer is a static apparatus, which receives power/energy at it, one circuit
and transmits it to other circuit without changing the frequency. With this basic
conception we can use the voltages at our desired level while utilizing the power.
As, the voltage used to generate at modern power houses at 11 KV or so and
afterwards we get it step up at a level of 33 KV, 66 KV, 132 V, 220 KV or 400
KV, 750 KV for transmission to minimize the distribution losses. Again we get it
step down with the help of transformer to use at our wishes at 11 KV, 6.6 KV or
even 415, 230 volts at our houses.
BASIC PARTS OF TRANSFORMER
The following are the inherent parts of a modern day transformer:
27 Dept. of Electrical Engg.
28. 1. Primary and secondary coils (circuit) or windings.
2. Core
3. Main Tank
4. Conservator
5. Breather
6. Radiator
7. Buchholz relay
8. Explosive vent
9. Bushings (HT & LT) (Primary or secondary)
10. Cooling fans
11. Tap changer (on load and off load)
12. NGR (Neutral Grounding Resistance) to minimize the earth fault current
Fig 6.1
DESCRIPTION OF PLANT:
28 Dept. of Electrical Engg.
29. The three transformer are oil immersed with rating of 250 MVA
& one with 315 MVA. However a synchronous loading of 100MVA at 0.8 power
factor (lag) and 18 MVA 0.8 pf (lag) on the tertiary can also be loaded to 20MVA
loading with 100MVA 0.8 pf on LV without exceeding the generated temperature
rise.
The transformer is also provided with a separate bank of
radiation, fans, and associated control equipments. The control equipments are
housed in a tank mounted miscalling.
Fig 6.2
RATING DATAS.
Type of cooling: ONAN / ONAF/ ODAF
29 Dept. of Electrical Engg.
30. MVA
HV: 189 / 252 / 315
IV: 189 / 252 / 315
LV: 63 / 84 / 105
VOLTS
HV: 400 KV
IV: 220 KV
LV: 33 KV
LINE AMPERES
HV: 273 / 364 / 455
IV: 497 / 662 / 828
LV: 1104 / 1471 /1839
IMPEDANCE VOLTAGE
HV to IV 12.65% on 315 MVA Base
HV to LV 39.16 % on 315MVA Base
IV to LV 26.66 % on 315 MVA Base
NUMBER OF PHASES
Three HV, LV, IV
FREQUENCY IN Hz
50 Hz
30 Dept. of Electrical Engg.
31. YEAR OF MANUFACTURE: 1985
Mass of Core & Windings: 1,32,000 kg
Mass of Oil: 65,150 kg
Total weight: 261,200 kg
Oil in tank: 73,200 kg
Oil in radiator: 8400 kg
Oil in tap changer: 83,850 kg
Transportation mass: 168,000 kg
Unmaking height: 7760 mm
Unmaking mass 18000 Kg
Guaranteed maximum temperature rise of:
Oil 45ºC
Winding 50ºC
COOLING FANS:
Rating: 2000 m3 of air per minute.
Type: 915 mm dial GEC (India) make.
Numbers per transformer: two
31 Dept. of Electrical Engg.
32. Fan motor: direct on line starts weather proof.
Squirrel cage IM 1400 W 400/440
Volt 3-φ , 50 Hz 720 rpm
PUMPS:
Rating: 1818 liters per minute.
Type: a landless A to 8c sentiment.
Number of pump per transformer: one working, one standby.
Pump motor: direct on line starts weather proof.
Squirrel cage IM
32 Dept. of Electrical Engg.
33. CURRENT TRANSFORMER
These transformers are used with low range ammeter to measure currents in high
voltage alternating current circuits where it is not practicable to connect
instruments and meters directly to lines. In addition to insulating the instrument
from the high voltage line, they step down the current in the known ratio. The
current (or series) transformers has a primary coil of 1 or more turns of thick wires
connected in series with the line whose current is to be measured. The secondary
consist of a large number of turns of fine wire and is connected across the ammeter
terminals (usually of 5 amp bracket should be removed or 1 amp range)
33 Dept. of Electrical Engg.
34. Fig 7
POTENTIAL TRANSFORMER
These transformers are extremely accurate ratio step down transformers and are
used in conjunction with standard low range voltmeter (usually 150 volt) whose
deflection when divided by voltage transformation ratio, gives the true voltage on
the high voltage side. In general, they are of the shell type and do not differ much
from the ordinary two winding transformer, except that their power rating is
extremely small. Up to voltage of 5000 potential transformers are usually of dry
type, between 5000 and 13800 volts, they may be either dry type or oil immersed
type, although for voltage above 13800 they are oil type. Since their secondary
windings are required to operate instruments or relays or pilot lights, their ratings
are usually 42 to 100 watts.
34 Dept. of Electrical Engg.
35. CAPACITIVE VOLTAGE TRANSFORMERS (CVT)
Capacitive voltage transformers are special kind of power
transformers using capacitors to step down the voltage.
DESCRIPTION:
35 Dept. of Electrical Engg.
36. The capacitive voltage transformer comprises of a capacitor divider
with its associated electromagnetic unit. The divider provides an accurate
proportioned voltage, while the magnetic unit transforms this voltage, in both
magnitude and phase to convenient levels suitable for measuring, metering,
protection etc. all WSI capacitor units has metallic bellows to compensate the
volumetric expansion of oil inside. The porcelain in multi unit stack, all the
potential points are electrically tied and suitably shielded to overcome the effect
of corona RIV etc. Capacitive voltage transformers are available for system
voltages of 33 KV to 420KV.
Fig 8
APPLICATION:
1. Capacitive voltage transformers can be effectively as potential sources for
measuring ,metering, protection, carrier communication and other vital
functions of an electrical network.
36 Dept. of Electrical Engg.
37. 2. CVT are constructed in single or multi unit porcelain housing with there
associated magnetic units. For EHV systemcuts are always supplied in multi
unit construction.
3. In case of EHV cuts the multi unit system has many advantage easy to
transport and storing, convenience in handling.
RATING OF CVT
Voltage: 22/sqrt 3 KV
Total o/p: 500MVA
Operating voltage: 400/sqrt 3 max.
Voltage factor: 1.5/30 sec.
Test voltage: 630 KV for 1 min
Impulse withstands voltage: 1.2/ 50 µs. 1425KV max.
Frequency : 50Hz
High frequency capacitance: 4400pF
Primary capacitance: 4657pF
Secondary capacitance: 80000 pF
S no Ie Make Ratio Burden Class Sec cap
1 Bassi Wsi/cve/420 400 200,200, 3p,3p,0.5 80000pf
/1425 100
2 Bassi 2 Wsi/cve/420 400 200,200, 3p,3p,0.5 80000pf
/1425 100
3 Bus 1 Wsi/cve/420 400 200,200, 3p,3p,0.5 80000pf
37 Dept. of Electrical Engg.
38. /1425 100
4 Bus 2 Wsi/cve/420 400 200,200, 3p,3p,0.5 80000pf
/1425 100
TRANSFORMER OIL & ITS TESTING
The prime function of oil is to convey the heat from the core and winding to the
tank where it can be dissipated. Besides these, the oil provides additional insulation
between primary and secondary windings. So, the oil must be completely free from
dirt, moisture and other un-wanted solid matter. The oil used in the transformer is
natural mineral oil and should undergo the following tests if required:
BREAKDOWN VOLTAGE:
The voltage at which the oil breaks down when subjected to an electric field.
FLASH POINT:
The temperature, at which the oil gives off so many vapors, when mixed with air
forms an ignitable mixture and gives a momentary flash with small pilot flame.
38 Dept. of Electrical Engg.
39. For checking above values, various tests are done. These are
categorized as:
1. Physical test.
2. Chemical test.
3. Electrical test.
The results must be close to standard results that are follows-
S.N TYPE OF TEST STD. RESULTS
1. Density (gm/cubic cm.)at 27°C .85 to .89
2. Flash point >125°C
3. B.D.V Test K.V (rms.) >50 KV
4. Tan delta at 90°C < 20%
5. Water content (PPM.) 25(max.)above 145KV
6. Gas contents (PPM.)
(a) Hydrogen 100 to150
(b) Methane 50 to 70
(c) Ethane 30 to 50
(d) Ethylene 100 to 150
(e) Acetylene 20 to 30
(f) Carbon dioxide 3000 to 3500
(h) Carbon mono-oxide 200 to300
39 Dept. of Electrical Engg.
40. LIGHTENING ARRESTORS
An electric discharge between cloud and earth, between cloud and the charge
centers of the same cloud is known as lightening.
The earthing screens and the ground wires can well protect the electrical system
against direct lightening strokes but they fail to provide protection against
travelling waves which may reach the terminal apparatus. The lightening arrestors
or the surge diverters provide protections against such surges.
THYRITE TYPE:
Ground wire run over the tower provides an adequate protection
against lighting and reduce the induced electrostatic or electromagnetic voltage but
such a shield is inadequate to protect any traveling wave, which reaches the
terminal of the electrical equipment, and such wave can cause the following
damage.
40 Dept. of Electrical Engg.
41. 1 the high peak of the surge may cause a flashover in the internal wiring
thus it may spoil the insulation of the winding .
2 the steep wave front may cause internal flash over between their turns of
transformer.
3 The stop wave front resulting into resonance and high voltage may cause
internal or external flashover causing building up the oscillator is the
electrical operation.
Lightening arrestors are provided between the line and earth provided the
protection against traveling wave surge the thyrite lightening arrestor are provided
at GSS. This type of LA has a basic cell made of thirties, which is a particular type
of clay, mixed with carborendum. Thirties has a particular property of being
insulator one voltage
At high voltage It will behave like a conducting material the electrical resistance of
thyrite depends upon the voltage each time the voltage is made twice the resistance
decrease in such a manner as to allow an increased current of 12.5 times the
change in current is independent of rate of application voltage and its instantaneous
value.
The above law is followed by this material without any limit on the voltage
increase and after the surge has passed the thyrite againretain its original property
A standard cell is rated for 1KV and is formed into a disc, which is sprayed on
both the sides of to give good contact with each disc. The dimensions of the discs
are stacked i.e. 16 cm in diameter and 17.5 cm thick these discs are stacked one
upon each other and they are further placed in to a porcelien container with a
suitable arrangement of gap between them.
41 Dept. of Electrical Engg.
42. These gaps serves as the purpose of preventing any current flow during
normal operating voltage in case of any transients the gap are punctured. The
Thyrite type arrestor will discharge several thousands ampere without the slightest
tendency of flashover on the edges of most important of the advance is that there is
absolutely no time lag in its performance.
400KV LIGHTNENIG ARRESTOR
manufacture: English electric company
no of phases: one
rated voltage: 360 KV
nominal discharge current (8×20µs) 10KA
high current impulse(4×110 µs ) 100KA
long duration rating(200 µs) 500KA
Sno Ie Make Type Current Voltage
1 Bassi1 Wsi Cpl 10KA 360KV
2 bassi2 Elpro Alugard2 10KA 360KV
3 ILT1 Elpro Alugard2 10KA 360KV
4 ILT2 Elpro Alugard2 10KA 360KVh
5 ILT3 WSI CDV303 10KA 398KV
6 ILT4 WSI CDV03 10KA 398KV
42 Dept. of Electrical Engg.
43. CONTROL PANEL
The diagram made on the control panel is known as mimic diagram.
COLOUR CODING
* 33KV GREEN
* 132 KV BLACK
* 220KV BROWN
* 440 VOLTS VOILET/INDIGO
* 110 VOLTS ORANGE
REACTOR
It is used to lower the over excited capacitor. Capacitor bank is connected in shunt
over the reactor. Capacitors main purpose is to boost up the voltage. so when we
want to lower the voltage we use reactors. it is also use to stop the sudden change.
the commonly used reactor is NGR(Neutral ground reactor).
43 Dept. of Electrical Engg.
44. CIRCUIT BREAKER
There is a one and half breaker scheme i.e. 3 breakers for 2 buses used in 400 KV
G.S.S.
BUS COUPLERS
It is used to equalize the load on both Bus bars.
DISTURBANCE RECORDER
It records the distance & fault on graph with voltage w.r.t time.
EVENT LOGGER
it monitors as well as provides the details as a printed material.
These details may contain the sequence of operation, switching time, closing time
etc.
ON LOAD TAP CHANGER (OLTC)
In this method a number of tappings are provided on the secondary of the
transformer. The voltage drop in the line is supplied by changing the secondary
emf of the transformer through the adjustment of its number of turns by using
transition resistor
which are placed in between each tapping.
44 Dept. of Electrical Engg.
45. In supply system, tap changing has to be performed on load so that here is no
interruption to supply. By using transition resister therefore shut down is not
required.
Fig 11
NO LOAD TAP CHANGER (NLTC)
in this we change the tap manually for which we have to shut down the
transformer.
When the load increases the voltage across the primary drops but the secondary
voltage can be kept at the previous value by placing the movable arm on to a
higher stud. Whenever a tapping is to be changed in this type of transformer, the
load is kept off and hence the name off load tap-changing transformer.
SYNCHRONOSCOPE
A synchronoscope is used to determine the correct instance of closing the switch
with connect the new supply to bus bar the correct instance of synchronizing is
indicated when bus bar and incoming voltage
45 Dept. of Electrical Engg.
46. * are equal in magnitude
* are equal in phase
* have the same frequency
the phase sequence is same
EARTHING OF THE SYSTEM:
The provision of an earthling system for an electric system is necessary by the
following reason.
1 In the event of over voltage on the system due to lightening discharge or
other system fault. These parts of equipment, which are normally dead, as
for as voltage, are concerned do not attain dangerously high potential.
2 In a three phase, circuit the neutral of the system is earthed in order to
stabilize the potential of circuit with respect to earth.
The resistance of earthling system is depending on
1 Shape and material of earth electrode used.
2 Depth in the soil
3 Specific resistance of soil surrounding in the neighborhood of system
electrodes.
PROCEDURE OF EARTHING:
Technical consideration the current carrying path should have enough capacity to
deal with more faults current. The resistance of earth and current path should be
low enough to prevent voltage rise between earth and neutral. The earth electrode
must be driven into the ground to a sufficient depth to as to obtain lower value of
earth resistance. To sufficient lowered earth resistance a number of electrodes are
inserted in the earth to a depth they are connected together to form a mesh. The
resistance of earth should be for the mesh in generally inserted in the earth at 0.5m
46 Dept. of Electrical Engg.
47. depths the several point of mesh then connected to earth electrode or ground
conduction. The earth electrode is metal plate copper is used for earth plate.
Neutral Earthing:
Neutral earthing of power transformer all power system operates with
grounded neutral. Grounding of neutral offers several advantages the neutral point
of generator transformer is connected to earth directly or through a reactance in
some cases the neutral points is earthed through an adjustable reactor of reactance
matched with the line. The earthling is one of the most important feature of system
design for switchgear protection neutral grounding is important because:
1 The earth fault protection is based on the method of neutral earthling.
2 The neutral earthling is associated switchgear.
3 The neutral earthling is provided for the purpose of protection arcing
grounds unbalanced voltages with respect to protection from lightening
and for improvement of system.
47 Dept. of Electrical Engg.
48. POWER LINE CARRIER COMMUNICATION
As electronics plays a vital role in the industrial growth, communication is also a
backbone of any power station, communication between various generating and
receiving station is very essential for proper operation of power system. This is
more so in case of a large interconnected system where a control load dispatch
station has to coordinate
the working of various units to see that the system is maintained in the optimum
working condition, power line communication is the most economical and reliable
method of communication for medium and long distance in a power network.
PLCC system in Rajasthan: -
1 HEERAPURA: JAIPUR, AJMER, BYAWAR, BHILWARA, PALI, JODHPUR
2 HISSAR: KHETRI, HEERAPURA, KOTA, RAPP
3 HEERAPURA: KOTS, JSP, RPS, GSD
4 BHILWARA: RPS
5 PALI: FALANA
6 HEERAPURA: ALWAR, BHARATPUR
7 NEEMUCH: DEBARI
8 DEBARI: SIROHI
48 Dept. of Electrical Engg.
49. 9 DEBARI: ZAWAR MINES
10 HEERAPURA: SIKAR, RATANGARH, BIKANER
11 HANUM, ANGARH: HISSAR, SHRIGANGANAGAR
12 HEERAPURA: BADHERPUB
CORONA EFFECT
When an alternating potential difference is applied across two conductors whose
spacing is as large as compared to their diameters, there is no apparent change in
the condition of atmospheric air surrounding the wires if the applied voltage is low.
However when the applied voltage exceeds a certain value called critical
disruptive voltage, the conductors are surrounded by a faint violet glow called
corona.
The phenomenon of corona is accompanied by a hissing sound, production
of ozone, power loss and radio interference. The higher the voltage is raised, the
larger and higher the luminous envelope becomes, and greater are the sound, the
power loss and the radio noise. If the applied voltage is increased to breakdown
value, a flash over will occur between the conductors due to the breakdown of air
insulation.
The phenomenon of violet glow, hissing noise and production of ozone gas
in an overhead transmission line is known as corona.
49 Dept. of Electrical Engg.
50. If the conductors are polished and smooth, the corona glow will be uniform
throughout the length of the conductors, otherwise the rough points will appear
brighter. The positive wire has uniform glow about it, while the negative
conductors has spotty glow.
FACTORS AFFECTING CORONA
The phenomenon of corona is affected by the physical state of the atmosphere as
well as by the conditions of the line. The following are the factors on which corona
depends:
1. Atmosphere. In the stormy weather, the number of ions is more than normal
and as such corona occurs at much less voltage as compared with fair
weather.
2. Conductor size. The rough and irregular surface will give rise to more
corona because unevenness of the surface decreases the value of breakdown
voltage.
3. Spacing between conductors. Larger space between conductors reduces the
electro-static stresses at the conductor surface, thus avoiding corona
formation.
4. Line voltage. If the line voltage is low, there is no chance in the condition of
air surrounding the conductors and hence no corona is formed.
50 Dept. of Electrical Engg.
51. ADVANTAGES AND DISADVANTAGES OF CORONA
Corona has many advantages and disadvantages. In the correct design of a high
voltage overhead line, a balance should be struck between the advantages and
disadvantages.
Advantages
1. Due to corona formation, the air surrounding the conductor becomes
conducting and hence virtual diameter of the conductor is increased. The
increased diameter reduces the electro-static stresses between the
conductors.
2. Corona reduces the effect of the transients produced by surges.
Disadvantages
1. Corona is accompanied by a loss of energy. This affects the transmission
efficiency of the line.
2. Ozone is produced by corona and may cause corrosion of the conductor due
to chemical action.
3. The current drawn by the line due to corona is non-sinusoidal and hence
non-sinusoidal voltage drop occurs in the line. This may cause inductive
interference with neighboring communication lines.
51 Dept. of Electrical Engg.
52. CONCLUSION
A technician needs to have not just theoretical but practical as well and so
every student is supposed to undergo a practical training session after III year
where I have imbibed the knowledge about transmission, distribution, generation
and maintenance with economical issues related to it.
During our 30 days training session we were acquainted with the repairing of
the transformers and also the testing of oil which is a major component of
transformer.
At last I would like to say that practical training taken at 220KV GSS has
broadened my knowledge and has widened my thinking as a professional.
52 Dept. of Electrical Engg.
53. REFERENCES:
Principles of Power System-by V.K.MEHTA
Electrical Power System-by C.L.WADHWA
REPORT BY-
Kapil Kumar
SKIT,JAIPUR
53 Dept. of Electrical Engg.